On a construction site, in particular for buildings, most of the work which has to be done requires some kind of spatial reference with respect to the worksite. While in former days a craftsman used pocket rule, square spirit level and construction plan drawings or linguistic instructions, nowadays there are often electronic tools to assist for those tasks.
For example EP 2 698 602 shows a handheld tool for electronic distance measurement (=EDM) with a support that has an angular joint providing angular reference information. Thereby geometrical Data of a room can be gathered. EP 2 458 328 shows a surveillance instrument for measuring and marking points at a construction site. It comprises a laser EDM and angular sensors and can be used for plumbing.
In EP 2 781 880 a construction laser system with a self leveling laser rotator and a laser receiver with calibration functionality is shown. EP 2 053 353 shows a reference line projection unit with an EDM and a visible reference laser beam guided along a defined reference path for projecting a reference line.
EP 2 453 205 shows a surveying instrument with an EDM to determine a distance, angular sensors to determine the orientation and a camera unit. The instrument provides a scanning function for determining a point cloud. The instrument of EP 2 620 746 for surveying and marking spatial coordinates in a room comprises an automatic leveling function for measuring and marking points along a horizontal line at a arbitrary shaped surface.
In EP 2 502 712, a method and system for determining the position of a hand-held power tool on a wall is presented.
The information gathered by such devices is often handled electronically in some Building Information Modeling system, also referenced as BIM. For example, the European patent application Nr. EP 15 153 842, which his herewith incorporated by reference, or EP 2 629 210, US 2014/268064, CN 103886139, JP 5489310, US 2014/192159, etc. mention examples of such Worksite management methods and systems.
Using a point-cloud generating laser-scanner device has the disadvantage that the processing of the point cloud is quite complex, requires lot of computing power and post processing. Capturing such a huge amount of measurement data not only takes a lot of time, but it is often not efficient for daily usage at a construction site, as only a small fraction of the gathered information is actually required and of use. Furthermore, such scanner devices are often damageable and not designed for rough in field usage.
On the other hand, simple handheld measurement tools like electronic distance meters (EDM), electronic levels or the like are often designed too simple, only providing some basic functions and the results are strongly dependent on skills and experience of the operator using them. At most, such handheld devices have very limited data exchange capabilities, so that the operator has to manually document his measurements, which is often a cause of human errors, insufficient or ambiguous information, etc.
Usage of a geodetic instrument like a theodolit or the like would be overkill for most of the applications. Beside the fact that such devices are expensive and require specialized training for the rather complicated usage, such high accuracy is seldom demanded. An ordinary craftsman could not handle such a device, but a skilled specialist would be required, which is not desirable as the general craftsman should be able to handle all his tasks as well as the post-work documentation on his own.